The present invention relates to a video data processing device and a video data display device suitable for displaying images or character information contained in video signals on a display device for computers such as a personal computer and a work station.
In recent years, the expectation of multimedia technique has risen, and there has increased the need of superimposing images of video signals for television, etc. for displaying on a graphic display screen for computers such as a personal computer (hereinafter, abbreviated to xe2x80x9cPCxe2x80x9d), and a work station (hereinafter, abbreviated to xe2x80x9cWSxe2x80x9d). Image display devices for realizing the need have also been developed and on sale.
Further in recent years, a PC obtained by incorporating a television tuner in addition to a mechanism of superimposing images of video signals on a graphic display screen has been on sale as a xe2x80x9cpersonal computer in which television can be seenxe2x80x9d.
There exist plenty of systems of superimposing image thus contained in video signals on a graphic screen for computers.
Recently, since buses (for example, PCI bus) having fast transfer velocity capable of transferring tremendous digital image data on real-time basis are being spread with PC or WS, there has been developed a system (hereinafter, referred to as xe2x80x9cdirect transfer systemxe2x80x9d) for displaying images by transferring digitized video signals to a memory for graphic display for PC or WS through bus.
With this direct transfer system, an image can be displayed only by transferring data through bus once and therefore, it is possible to transfer a large quantity of image data within unit time, and to display high-quality images.
In this respect, for detail of this direct transfer system, refer to the April 1996 issue of Interface Journal (on pages 102 to 109) published by CQ Publishing Company.
Also, in Japanese Patent Laid-Open Application No.6-124189, there is disclosed a technique of superimposing images in video signals on a graphic screen for displaying by using the direct transfer system.
On the other hand, some video signals contain character information in addition to images. For example, Closed Caption (hereinafter, abbreviated to xe2x80x9cCCxe2x80x9d) standardized by FCC (Federal Communications Commission) in the United States is a system of multiplexing character information such as captions in addition to images.
In the United States, they are multiplexing, to video signals, character information related to screen by using this CC system for persons who have difficulty in hearing. Particularly, as from Apr. 1, 1993, the law obliged all television sets of 13 inch or more sold in the United States to correspond to the CC system.
With the CC system, character information is multiplexed to the area of a period which is not displayed in a screen called a xe2x80x9cvertical blanking intervalxe2x80x9d among video signals. For this reason, character information multiplexed by the CC system is not displayed on the screen in television sets, etc. having no decoder of the CC system, but when a television set in which a decoder of the CC system is incorporated receives video signals with character information multiplexed, the captions can be seen together with images.
Currently, there are television sets etc., on the market, which are capable of displaying, on the screen, characters obtained by decoding character information multiplexed to video signals by using the CC system. And there are also a decoding device or VTR (Video Tape Recorder), on the market, having a function to multiplex character information for outputting, which is multiplexed to video signals by the CC system, to images likewise contained in the video signals.
The technique related to the above described in the Interface Journal or the technique disclosed in the Japanese Patent Laid-Open Application No.6-124189 had the problem that no consideration has been paid to character information contained in video signals.
This is because the appropriate treating methods in PC are different between video data such as images and data of character information.
Generally, video data such as images have a large amount of data, and a load is applied to the system in the mode of execution in which CPU of computer interprets software, and therefore, exclusive hardware such as image board of MPEG board, etc. is mostly prepared. Also, when video data are transferred to CPU, there is also the problem that the traffic of bus increases to lower the performance of the entire system.
On the other hand, the character information has smaller amount of data than the video data, and is suitable for the mode of execution in which CPU interprets software. Processing of this character information by the use of exclusive hardware has the problem that the device will be larger in size and expensive. Also, preparation of the respective exclusive hardware every time character information is processed has the problem that it lacks flexibility. Further, the use of the exclusive hardware has the problem that the power consumption will be high.
When images and characters are thus superimposed on a graphic display screen, there is the problem that the processes for video data and character information data must be properly divided into a process by the exclusive hardware and a process in which CPU interprets the software for execution.
The object of the present invention is to provide a video data processing device and a video data display device which are small-sized, low-priced and have less power consumption without lowering the display performance as the entire system in such a manner that when video data such as images and character information are superimposed to display on a graphic display screen, an appropriate process can be performed in accordance with the property of the data.
In order to achieve the aforesaid object, a video data processing device according to the present invention is constructed such that in a video data processing device for inputting video data consisting of vertical blanking interval data and other image data than vertical blanking interval for processing, the device comprises video data inputting means for inputting the aforesaid video data, and data transfer means capable of transferring the vertical blanking interval data and other image data than the vertical blanking interval, of the aforesaid video data, to different devices from each other so that the aforesaid vertical blanking interval data and the other image data than the vertical blanking interval can be processed individually.
More specifically, the video data processing device comprises scaling means for scaling the video data at a designated scaling ratio, and color format conversion means for color format converting the video data with a designated color format so that the scaling means scales the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, at scaling ratios different from each other, and the aforesaid color format conversion means color format converts the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, by means of color format conversion methods different from each other.
Specifically, in the video data processing device, which is a computer provided with a processor, a main memory and a graphic display memory, the data transfer means DMA (Direct Memory Access) transfers the vertical blanking interval data to the main memory, and the other image data than the vertical blanking interval to the graphic display memory respectively.
Further specifically, in the video data processing device, which is a computer provided with a processor, a main memory and a graphic display memory, the data transfer means DMA (Direct Memory Access) transfers the vertical blanking interval data to the main memory, and the other image data than the vertical blanking interval to the main memory and the graphic display memory respectively.
Further specifically, the data transfer means transfers, in the video data processing device, the vertical blanking interval data contained in the video data in preference to the image data of the vertical blanking interval data.
Next, in order to achieve the aforesaid object, a first configuration of a video data display device according to the present invention is such that, in the video data display device for inputting video data consisting of vertical blanking interval data and other image data than the vertical blanking interval for displaying, moreover the vertical blanking interval data having a format capable of containing character information, the device comprises video data inputting means for inputting the video data, data transfer means capable of transferring the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, to different devices from each other, decoding means for decoding the vertical blanking interval data to generate character data, and display means for displaying the character data thus decoded.
More specifically, the video data display device comprises scaling means for scaling the video data at a designated scaling ratio, and color format conversion means for color format converting the video data with a designated color format so that the scaling means scales the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, at scaling ratios different from each other, and the aforesaid color format conversion means color format converts the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, by means of color format conversion methods different from each other.
Next, in order to achieve the aforesaid object, a second configuration of a video data display device according to the present invention is such that, in the video data display device for inputting video data consisting of vertical blanking interval data and other image data than the vertical blanking interval for displaying, moreover, the vertical blanking interval data having a format capable of containing character information, the device comprises video data inputting means for inputting the video data, data transfer means capable of transferring the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, to different devices from each other, decoding means for decoding the vertical blanking interval data to generate character data, and storage means for storing the character data thus decoded.
Also specifically, the video data display device comprises scaling means for scaling the video data at a designated scaling ratio, and color format conversion means for color format converting the video data with a designated color format so that the scaling means scales the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, at scaling ratios different from each other, and the aforesaid color format conversion means color format converts the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, by means of color format conversion methods different from each other.
More specifically, the video data processing device has a processor, and the decoding means performs decoding when the processor interprets and executes the program.
Also, specifically, in the video data display device, the decoding means discriminates whether or not character information is contained in the vertical blanking interval data, and when character information is contained in the vertical blanking interval data, the decoding means controls the data transfer means so as to transfer the vertical blanking interval data. When no character information is contained in the vertical blanking interval data, it controls the data transfer means so as to stop the transfer of the vertical blanking interval data.
Further specifically, in the video data display device, the decoding means discriminates the classification of character information contained in the aforesaid vertical blanking interval data to control the data transfer means, transfers the vertical blanking interval data required to decode the character information contained in the vertical blanking interval data to control the data transfer means, and prevents vertical blanking interval data not required to decode the character information contained in the vertical blanking interval data from being transferred.
Next, in order to achieve the aforesaid object, a third configuration of a video data display device according to the present invention is such that, in the video data display device for inputting video data consisting of vertical blanking interval data and other image data than the vertical blanking interval for displaying, moreover, the vertical blanking interval data having a format capable of containing character information, the device comprises video data inputting means for inputting the video data; scaling means for scaling the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, at scaling ratios different from each other; color format conversion means for color format converting the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, by means of color format conversion methods different from each other; data transfer means capable of transferring the vertical blanking interval data and other image data than the vertical blanking interval data, of the aforesaid video data, to devices different from each other; and further graphic display means, the graphic display means including the color format conversion means for the video data and the scaling display means.
More specifically, in the video data display device, when the amount of the image data increases by means of color format conversion of the image data contained in the video data, the color format conversion is performed by the graphic display means. When the amount of the image data decreases or does not change by means of the color format conversion of the image data contained in the video data, the color format conversion is performed by the color format conversion means separately provided from the aforesaid graphic display means.
More specifically, in the video data display device, when the amount of the image data increases by means of scaling of the image data contained in the video data, scaling is performed by the graphic display means. When the amount of the image data decreases or does not change by means of scaling of the image data contained in the video data, scaling is performed by means of scaling means separately provided from the aforesaid graphic display means.
Further specifically, the data transfer means transfers, in the video data display device, the vertical blanking interval data contained in the video data in preference to the image data contained in the video data.
As described above, according to a video data processing device and a video data display device according to the present invention, image data contained in video signals are directly transferred to a graphic display memory, and character information data contained in video signals, to a main memory through bus respectively, and by further decoding and displaying the character information by means of CPU, it is possible to allocate a process on images and a process of displaying character information by taking into consideration balance as the system, and to make the device low-priced, and small-sized with low power consumption, and yet to display both high-quality graphics and images.